Hermetically-enclosed refrigerating machines



June 8, 1965 K. ROELSGAARD 3,187,991

HERMEI'IGALLY-ENCLOSED REFRIGERATING MACHINES Filed Nov. 27. 1961 FIG.

um! mu United States Patent 0 This invention relates to a hermeticallyenclosed motor compressor, especially a refrigerant compressor containing suctionand pressure silencers or mufiiers.

The major problem in hermetically-enclosed motor compressors is the removal of the heat produced interiorly of the hermetically-sealed capsule which encloses the compressor assembly. This heat is the result of heat emission from the electric motor, the heat of compression of the gas, and the heat of friction in the moving parts. The problem is to remove this heat from the capsule in a manner such that damaging superheating does not occur, even locally. Too high a temperature in the cylinder and bearing areas is particularly undesirable because the compressor capacity is thereby reduced considerably and, in the bearing, the lubricating etliciency of the oil is simultaneously decreased. The cylinder and the bearing both have substantially the same temperature because they are generally constructed with or mounted on a common supporting body and they are thus in a heat-transferring relationship to each other.

It is accordingly an object of this invention to provide a construction in a hermetically-enclosed motor compressor which favors heat removal in a manner which avoids any local overheating.

According to the invention, a reduction of temperature at the areas specified, and interiorly of the capsule as a Whole, is achieved by a re-arrangement of the parts of the compressor assembly. More particularly, in accordance with the invention, the silencer in the suction line is in heat-conducting relationships with the cylinder, and the silencer in the pressure line is disposed at a distance from the cylinder.

By reason of these relationships, it is possible to cool the cylinder by means of the relatively cool gas which is .under suction pressure, whereas the relatively warm gas under higher pressure is immediately carried away from the exterior of the cylinder. A disturbing and dangerous heat transfer to the cylinder, the supporting element and the bearing can, therefore, not occur. The silencer in the pressure line from which, because of the gas turbulence in its interior and because of its rather large surface, a considerable heat emission normally occurs, has thus been removed from the zones which it is desired to protect.

Furthermore, the silencer can be placed outside the capsule, if desired. Such a combination has not heretofore been known. Motor compressors are known wherein the silencer inthe suction line and the silencer in the pressure line are mounted in the suction line and in the pressure line, respectively, in such manner that they are separated from the compressor. However, because of the lack of cooling, both the compressor and the earing have relatively high temperatures. Motor compressors wherein both the silencer in the suction line and the silencer in the pressure line are mounted in the vicinity of the cylinder and thus are in heat-conducting relationship with the cylinder are also known. In this construction, the cooling effect obtained, for example, by means of the suction gas is completely nullified by the heating effect of the compressed gas.

Finally, a construction is also known wherein the silencer in the suction line is disposed away from the compressor and the silencer in the pressure line is placed directly on the cylinder. This construction brings about even Worse temperature conditions.

in accordance with the invention, the silencer in the suction side can consist of one or more chambers placed either on one side, on both sides, or around the entire circumference of the cylinder sleeve. Because of the placement of the silencer in the vicinity of the cylinder, an especially excellent cooling is obtained and the greater the surface of the cylinder sleeve, the better the result because this surface is surrounded by the suction gas. In a motor compressor in which the interior capsule chamher is under suction pressure, it is an advantage to place the silencer in the pressure line inside the capsule suction chamber and to provide it with means to reduce heat emission. In this manner it is possible to insure that, in spite of the disposition of the pressure line silencer inside the capsule, the heat transmitted from the silencer in the pressure line to the suction gas ill be slight and, thus the overall temperature in the capsule will be considerably reduced.

Other objects and features of the invention will be apparent from the following detailed description of illustrative embodiments taken in connection with the accompanying drawing wherein,

FIG. 1 is an elevational view of a motor compressor disposed inside a capsule, shown in section, and embodying features of the present invention; and

FlG. 2 is a cross-sectional view through a supporting body having cast cylinder and silencing chambers according to a second embodiment.

Referring to the drawing, FIG. 1 shows in section a capsule consisting of a lower part 1 and a cover 2, all of conventional construction. The motor compressor is movably mounted interiorly of the capsule by means of springs also in conventional manner, only one spring being shown.

The springs engage a supporting body 5 which contains the stator of the motor 6 and which at the same time supports the rotor of the motor in a bearing. This arrangement is such that a centrifugal oil pump 7 can be immersed in an oil sump 3. The supporting element 5 also supports, by means of a connecting member (not shown) the cylinder iii, of which the rear side, i.e. t e valve cover ill with the suction valve chamber and the pressure valve chamber, is schematically shown.

The side extensions 12 and 13 of the cylinder contain the suction line silencer chambers, which can be connected in series or in parallel. From the silencer 13, a connecting line 14 leads to the chamber of the suction valve. From the pressure valve chamber a line 15 leads to the silencer 16 in the pressure line to which the remainder of the pressure line 17 is also connected. The gas flowing through chambers of the silencer in the suction line cools the cylinder and the parts connected to it, especially the supporting body 5 containing the bearing of the crankshaft. The compressed gas is immediately carried away from the cylinder construction through the line i5, and can at the earliest give off substantial heat in the silencer 16 in the pressure line. A retroactive heat transmission through the tube 15 is, as a rule, prevented because no corresponding temperature gradient exists between pressure silencer 1'6 and cylinder it). However, in order further to exclude the possibility of such retroactive heat transmission, the line 15 can be constructed of a material of poor heat conductivity, such as stainless steel. To prevent the gas in the capsule from being heated by the silencer 16 in the pressure line and thereby partly nullifing the desired effect, the silencer in the pressure line is provided with heat insulaareas-a1 tion 18 which, in its most simple form, consists of a foil cover which prevents direct contact of gas and oil on the walls of the silencer 116 in the pressure line and also hinders flow over these surfaces which would tend to increase heat transfer. In similar manner, the entire pressure line 317 can be provided with an enclosure which reduces heat emission or transfer.

FIG. 2 shows an embodiment of a supporting element 19, corresponding to the supporting body 5, with a cast cylinder, a suction silencing chamber, and a bearing disposed, as seen in cross-section, externally of the center axis of the element and forwardly of the bearing. It is seen that the supporting element 19 is formed with a bearing 20 on its side facing the motor and on its opposite side is disposed the cylinder 21, which is surrounded by two suction silencer chambers 22 and 23. The silencer chambers 22 and 2:3 enclose the free surface of the cylinder and are connected to each other by means of the port 24. With this construction, the cooling of the cylinder walls takes place over the greatest possible area of the surrounding surface.

The principle of the present invention can be utilized not only in connection with refrigerant compressors but wherever a reduction in the temperature inside the capsule of an enclosed motor compressor unit is required, for example in air compressors for paint spraying units, air compressors for auto repair shops, as well as all other gas compressors. In all of these cases, an increase in capacity and an improvement in the lubrication of the shaft bearing can be obtained in relation to known compressor constructions.

The motor and the compressor per se are not part of the present invention and they can be of conventional construction, subject to the structural changes relating to heat removal described and illustrated which are characteristic of the present invention. A typical motor compressor in which the present invention can be embodied is described, for example, in US. Patent No. 2,312,596. The motor and compressor can also be, for example, of the construction shown in my co-pending application filed November 13, 1961 entitled Lubricating Device for a Motor Compressor.

It will also be understood that various changes and modifications may be made in the embodiments described above and illustrated in the drawing without departing from the scope of the invention as defined in the appended claims.

It is intended, therefore, that all matter contained in the foregoing description and in the drawing shall be interpreted as illustrative only and not as limitative of the invention.

I claim:

I. In a hermetically-enclosed motor compressor comprising a compressor unit disposed within a hermeticallysealed capsule, said compressor unit including a cylinder for receiving a piston and driving means for reciprocating said piston in said cylinder for compressing a gaseous fluid therein, the combination with said cylinder of a pressure silencer internally of said capsule spaced from said cylinder as well as from the other components of said compressor unit and having no direct heat-conducting relationship with said cylinder and with said other components, and a pressure conduit extending outwardly from said cylinder to a point remote from said cylinder and from said other components and providing communication between said cylinder and said pressure silencer, said pressure silencer being disposed at said point and means insulating said silencer to preclude heat transfer from said silencer to the interior of said capsule.

2. In a hermetically-enclosed motor compressor comprising a compressor unit disposed spring-mounted within a hermetically-sealed capsule, said compressor unit including a cylinder for receiving a piston and driving means for reciprocating said piston in said cylinder, the

combination with said cylinder of a suction silencer connected to the suction side of said compressor unit and in direct heat-conducting relationship with said cylinder, and a pressure silencer spaced from said cylinder as well as from the other components of said compressor unit and having no direct heat-conducting relationship with said cylinder and with said other components and communieating with said cylinder only through a pressure conduit extending outwardly from said cylinder to a point remote from said cylinder and from said other components, said pressure silencer being disposed at said point, said suction silencer consisting of at least one chamber disposed directly along the circumference of said cylinder in direct heat'conducting relationship therewith.

3. In a hermetically enclosed motor compressor comprising a compressor unit disposed spring-mounted within a hermetically-sealed capsule, said compressor unit including a cylinder for receiving a piston and driving means for reciprocating said piston in said cylinder, the combination with said cylinder of a suction silencer connected to the suction side of said compressor unit and in direct heat-conducting relationship with said cylinder, and a pressure silencer spaced from said cylinder as well as from the other components of said compressor unit and having no direct heat-conducting relationship with said cylinder and with said other components and communicating with said cylinder only through a pressure conduit extending outwardly from said cylinder to a point remote from said cylinder and from said other components, said pressure silencer being disposed at said point, said suction silencer consisting of a plurality of chambers disposed along the circumference of the cylinder in direct heat-conducting relationship therewith.

4. In a hermetically-enclosed motor compressor comprising a compressor unit disposed spring-mounted within a hermetically-sealed capsule, said compressor unit including a cylinder for receiving a piston and driving means for reciprocating said piston in said cylinder, the combination with said cylinder of a suction silencer connected to the suction side of said compressor unit and in direct heat-conducting relationship with said cylinder, and a pressure silencer spaced from said cylinder as well as from the other components of said compressor unit and having no direct heat-conducting relationship with said cylinder and with said other components and communicating with said cylinder only through a pressure conduit extending outwardly from said cylinder to a point remote from said cylinder and from said other components, said pressure silencer being disposed at said point, said suction silencer consisting of at least one chamber disposed directly along the circumference of said cylinder in direct heat-conducting relationship therewith, the interior of said capsule defining a chamber under suction pressure, and said pressure silencer being disposed in the suction chamber of the capsule.

5. In a hermetically-enclosed motor compressor comprising a compressor unit disposed spring-mounted within a hermetically-sealed capsule, said compressor unit including a cylinder for receiving a piston and driving means for reciprocating said piston in said cylinder, the combination with said cylinder of a suction silencer connected to the suction side of said compressor unit and in direct heat-conducting-relationship with said cylinder, and a pressure silencer spaced from said cylinder as well as from the other components of said compressor unit and having no direct heat-conducting relationship with said cylinder and with said other components and communicating with said cylinder only through a pressure conduit extending outwardly from said cylinder to a point remote from said cylinder and from said other components, said pressure silencer being disposed at said point, said suction silencer consisting of a plurality of chambers disposed along the circumference of the cyl- 5 inder in direct heat-conducting relationship therewith, the interior of said capsule defining a chamber under suction pressure, and said pressure silencer being disposed in the suction chamber of the capsule.

6. In a hermetically-enclosed motor compressor comprising a compressor unit disposed spring-mounted Within a hermetically-sealed capsule, said compressor unit including a cylinder for receiving a piston and driving means for reciprocating said piston in said cylinder, the combination with said cylinder of a suction silencer internally of said capsule connected to the suction side of said compressor unit and in direct heat-conducting relationship with said cylinder, and a pressure silencer internally of said capsule spaced from said cylinder as Well as from the other components of said compressor unit, a pressure conduit providing communication between the cylinder and said pressure silencer, said pressure silencer having no direct heat-conducting relationship with said cylinder and with said other components and communieating with said cylinder only through said pressure con duit extending outwardly from said cylinder to a point remote from said cylinder and from said other com- 6 ponents, said pressure silencer being disposed at said point, said pressure conduit comprising a material of low heat conductivity and insulation means insulating said pressure silencer from the interior of said capsule.

References Cited by the Examiner UNITED STATES PATENTS 2,789,652 4/57 Fannen 181-36 2,823,850 2/58 Hintze 230-232 X 2,883,100 4/59 Harter 230-232 X 2,935,244 5/60 Dills 230-232 X 2,978,881 4/61 Alsing 62-505 X 3,033,609 5/62 Berger 62-469 FOREIGN PATENTS 537,896 5/55 Belgium.

KARL J. ALBRECHT, Primary Examiner.

LAURENCE V. EFNER, JOSEPH H. BRANSON, JR., Examiners. 

1. IN A HERMETICALLY-ENCLOSED MOTOR COMPRESSOR COMPRISING A COMPRESSOR UNIT DISPOSED WITHIN A HERMETICALLYSEALED CAPSULE, SAID COMPRESSOR UNIT INCLUDING A CYLINDER FOR RECEIVING A PISTON AND DRIVING MEANS FOR RECIPROCATING SAID PISTON IN SAID CYLINDER FOR COMPRESSING A GASEOUS FLUID THEREIN, THE COMBINATION WITH SAID CYLINDER OF A PRESSURE SILENCER INTERNALLY OF SAID CAPSULE SPACED FROM SAID CYLINDER AS WELL AS FROM THE OTHER COMPONENTS OF SAID COMPRESSOR UNIT AND HAVING NO DIRECT HEAT-CONDUCTING RELATIONSHIP WITH SAID CYLINDER AND WITH SAID OTHER COMPONENTS, AND A PRESSURE CONDUIT EXTENDING OUTWARDLY FROM SAID CYLINDER TO A POINT REMOTE FROM SAID CYLINDER AND FROM SAID OTHER COMPONENTS AND PROVIDING COMMUNICATION BETWEEN SAID CYLINDER AND SAID PRESSURE SILENCER, SAID PRESSURE SILENCER BEING DISPOSED AT SAID POINT AND MEANS INSULATING SAID SILENCER TO PRECLUDE HEAT TRANSFER FROM SAID SILENCER TO THE INTERIOR OF SAID CAPSULE. 